Mysteries persist about the origins of Covid, says WHO report

In its first report, a team of international scientists brought together by the World Health Organization to advise on the origins of the coronavirus said on Thursday that bats likely carried an ancestor of the coronavirus that may have spread to a mammal sold at a food market. wild life. . But the team said more Chinese data is needed to study how the virus spread to people, including the possibility that a lab leak played a role.

The team, appointed by the WHO in October as the organization tried to redefine its approach to studying the origins of the pandemic, said Chinese scientists had shared information with them, including from unpublished studies, on two occasions. But gaps in Chinese reports made it difficult to determine when and where the outbreak emerged, according to the report.

Independent experts said it was unclear how the team, made up of scientists from the United States, China and two dozen other countries, could help the WHO break through the political barriers in China that have prevented the publication of most of the information that would put the emergence of the virus within the country’s borders.

“China’s lack of political cooperation continues to stifle any significant progress,” said Lawrence Gostin, who directs the O’Neill Institute for National and Global Health Law at Georgetown University. He said the report offers a roadmap for investigating future pandemics in less secretive countries.

The WHO asked the group for advice not only to study the origins of the coronavirus, but also to examine the emergence of future pathogens. The team, known as the Scientific Advisory Group on the Origins of New Pathogens, does not have the authority to carry out investigations in China or elsewhere.

Maria Van Kerkhove, the WHO’s Covid-19 technical lead, said the report was “just the beginning of her work”.

The group was expected to indicate more openness to a laboratory leak than a previous team the WHO sent to China in early 2021. This previous team’s joint report with China said that a laboratory leak, while possible, was “extremely unlikely”. WHO Director-General Tedros Adhanom Ghebreyesus called this assessment premature.

The latest report said that no new data pointed to a lab leak. But the group’s leaders said they wanted to assess any evidence that emerged in the future.

“We have not received any reports that actually indicate that there is a laboratory leak that we think is strong to track,” said Marietjie Venter, team chair and professor of medical virology at the University of Pretoria in South Africa.

Efforts to study a laboratory leak met resistance from team members in China, Russia and Brazil, who saw no need for such investigations, the report said.

The report cited a number of studies on the potential role of animals in the emergence of the coronavirus that have been published since previous work by the WHO team. For example, research at a live animal market in Wuhan, China, indicated that several species known to be susceptible to the coronavirus were present in autumn 2019.

When people linked to that market started getting sick, police closed and disinfected the facility, making it more difficult for scientists to identify potential intermediate animal hosts for the virus.

The latest report said it was focusing on published, peer-reviewed studies, although it acknowledged a number of unpublished studies posted online as “preprints.” Among them were two papers released this year in which a team of scientists argued that the pandemic came about when a bat infected a wild animal, such as a raccoon dog, which was then sold at Huanan Seafood Wholesale. Market in Wuhan.

Michael Worobey, an evolutionary biologist at the University of Arizona who helped carry out these studies, said it is unfortunate that the WHO team did not take a close look at the unpublished research.

“I think if you read our preprints and understand the evidence,” he said, “there is actually very strong evidence that the pandemic came about through wildlife in the Huanan market.”

Dr. Worobey and other researchers said a vital opportunity was missed in January 2020 to focus the search for the coronavirus on wildlife farms that supplied markets like Huanan. Instead, millions of animals were slaughtered.

Filippa Lentzos, a biosafety researcher at King’s College London, praised the latest report for noting the lack of published findings from studies of origin in China itself. But she said her proposals for future studies of pandemic origin did not adequately account for investigations into “accidental or deliberate events,” which she said would require experience outside of public health.

Jesse Bloom, a virologist at the Fred Hutchinson Cancer Research Center, said the report made it clear that mitigating future pandemic threats required considering both animal and laboratory origins.

“Both are serious enough possibilities that they need to be thought about together,” he said.

The report recommended studies of blood samples from workers at wildlife farms and live animal markets and of genomic data from early viral samples. But the previous WHO team had proposed some similar studies, to no avail.

The latest report said that Dr. Tedros wrote twice to Chinese officials in February requesting information on the status of these studies, as well as information about a potential lab leak. But there was no indication that the WHO would be able to persuade China to share the results of such work.

Despite the difficulties, however, some information from China was leaked.

Last week, Chinese researchers published a small study on raccoon dogs and bats collected in the Wuhan region in January 2020. In 15 raccoon dogs, researchers found a new species of coronavirus related to one that infects dogs. In 334 bats, the researchers found coronaviruses that appear to be a mixture of viruses, some related to what caused Covid and others related to what caused SARS in 2003.

“These sample sizes are not large enough,” said Maciej Boni, a virologist at Penn State University. “We need sampling done at the scale of tens of thousands of bats to get a complete picture.”

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